The color conversion-type liquid crystal display (LCD) which uses fluorescent materials is particularly excellent in viewing angle properties than general LCDs with white light source and RGB color filters. In addition, a color conversion-type OLED display (the OLED device) using the fluorescent materials also has properties such as high resolution, low power consumption, and a wide viewing angle, as compared with separated red-green-blue (RGB) OLED subpixel type or white OLED with RGB color filters. Thus, further technical development of color-conversion type displays has been expected. The liquid crystal display and the OLED display are commonly provided with a color conversion material (CCM) substrate (a wavelength conversion substrate). The substrate generates red-green-blue (RGB) colors; red and green lights are emitted by fluorescent dyes where blue or ultra-violet light is converted into red or green light and blue backlight or blue-OLED is directly used for a blue subpixel.
The CCM substrate is typically configured to include a light-emitting layer including the fluorescent materials on a substrate, and is formed to further include a bank for partitioning the light-emitting layer on the substrate so as to prevent colors mixing between subpixels and to improve light extraction efficiency (refer to PTL 1). In addition, providing the bank for partitioning the light-emitting layer on the substrate has been proposed in order to efficiently reflect and guide the isotropical light, particularly the light propagating in the horizontal direction with respect to the substrate surface to the observer side (refer to PTL 2).
On the other hand, in the above-described displays, there is a problem in that the width of the bank becomes smaller (distance between partitions of the light-emitting layers becomes shorter) along with the development of high-resolution and high aperture ratio of a pixel, and in accordance with, the proportion of light transmitting through the banks (light transmittance of the bank) becomes increased, thereby deteriorating the light extraction efficiency with respect to an observer. In a case where the light extraction efficiency is deteriorated as described above, in order to obtain a desired amount of light at the observer side, the power consumption becomes higher. Even in a case where the bank includes, for example, titanium oxide having low light transmittance and high light reflectance, as the width of the banks becomes smaller, the light transmittance becomes higher. In this regard, a method to lower the light transmittance of the bank with a reflective film (a light reflective layer) comprising metal or the like on a surface (a surface of the bank which contacts with the light-emitting layer) of the bank which faces the light-emitting layer has been proposed (refer to PTL 3).